Insecticides



' Patented Jan. 18, 1938 UNITED STATES PATENT OFFICE No Drawing.Original application January 6,

1933, Serial No. 650,505. Divided and this application September 8,1936, Serial No. 99,817

3 Claims.

This invention relates to the production of substances for killinginsects, including red spiders and their eggs, and has been found to beparticularly efiicient in exterminating those red 5 spiders and theireggs which are found on citrus plants. The invention, therefore, hasamong its objects, to provide substances which, although well adaptedfor general use, are particularly adapted for use on citrus plants,delicate plants of various kinds, outdoors or indoors, and which areadapted to kill red spiders and eggs without damage to the plant,whatever the stage of growth of the plant or spider.

This application is divisional of my 'copending application, SerialNumber 650,505, filed Janumy 6, 1933, and now Patent No. 2,068,742, forInsecticides.

In the invention of my copending application, Serial Number 587,147 forInsecticides, filed January 16, 1932, now Patent No. 2,017,594, Idisclose, among other things, that new and very eflicient insecticidescan be produced by using selenium dissolved in alkaline sulphidesolutions. I also disclosed in the aforesaid application, newinsecticidal substances formed by chemically combining an alkali,sulphur and selenium.

In that application the sulphides used were monosulphides, such as KzS,NazS, KNHiS. As a result of extended investigations, including manyexperiments, I have now discovered that the polysulphides, such as K282,K253, K284, KzSs, 3952, Bass, BaS4, Bass do, when combined withselenium, form insecticides which are particularly efiicient forkillingmed spiders, and, in fact, it now seems clear that all complexpolyselenides of the alkali or alkaline earth metals are particularlyefiicient for this purpose.

The present invention, therefore, relates to new insecticidal materialsmade by combining selenium with any polysulphide of calcium, sodium orpotassium, etc., or with any soluble complex polysulphide.

To understand the invention, some discussion a of the chemical structureof sulphides in general seems advisable.

(l) The hydro sulphides KHS, NaHS, Ba(HS) 2, Ca(HS)2 are formed bysaturating the alkali solution KOH, Ba(OH)2 etc. with hydrogen sulphide.

(2) The sulphides KzS, NazS, BaS, CaS, etc, are formed by saturating thealkali solution with hydrogen sulphide as in (1) and then adding anequivalent amount of alkali solution.

The equation for (1) may be Ba (OH) 2+2H2S=Ba(HS) 2+2H2O and theequation for (2) may be Ba(HS) z+Ba(OH) 2=2BaS+2H2O.

(3) The polysulphides K282, K283, K234, K255, etc., and East, BaSa,BaS4, Bass, etc., can be made by dissolving sulphur in themono-sulphides, or by heating alkaline solution with sulphur. Thereactions may be represented as follows:

This latter product is lime sulphur of commerce. Most of the 335203 orCaSzOa is insoluble and is precipitated.

I claim herein, in addition to other matters, selenides of the typeequivalent to the polysulphides (3) above. The following are examples:

I do not wish to be limited to these examples, but claim as insecticidesthe polyselenides as a class whether formed as above, or formed by someother re-action, and I wish to include polyselenides of the alkali andalkaline earth metals.

It is intended to include complex selenides made by dissolving seleniumin the polysulphides, for example:

K2S2+Se; or BaSa-i-Se, etc.

and to include any solution of selenium in a polysulphide solution. I,therefore, claim herein'selenides of the type equivalent to thepolysulphides in (3) above.

An excellent and very toxic insecticide is made by making a solution ofthree ounces of selenium in one gallon of calcium polysulphide solution.This is used at a dilution of one gallon to five hundred gallons ofwater, or one-fifth of one per cent. This is very efi'ective againstcitrus red spiders at this dilution, whereas lime sulphur at thisdilution is not effective. Commercial lime sulphur alone is used at muchhigher concentration, the minimum for red spiders being about one andone-half per cent or one gallon to sixty-six gallons of water, and evenat this concentration it is not entirely eflective.

Although selenium polysulphides of alkali and alkaline earth metals areclaimed herein, l have further discovered that by using oil with any ofthe substances disclosed in the aforesaid copending application, agreater kill of red spiders at less concentration of both substances canbe obtained. I, therefore, claim herein substances for the control ofred spiders on plants, which include soluble, as well as insoluble,seleno-sulphides, and also seleno-polysulphides, in combination withoil, preferably mineral oil.

A good combination of oil spray with a selenium spray is prepared asfollows: Dissolve three ounces of selenium in one gallon of commerciallime sulphur (calcium polysulphide). Make a tank mix oil sprayemulsifying a suitable spray oil with blood albumen, calcium caseinateor other emulsifier, or use any suitable commercial emulsified oil. Theproportion of oil in the spray should be about one-third of a gallon ofoil to one hundred gallons of the spray,

or one-third of one percent. To the one hundred gallons of this oilspray add one gallon of lime sulphur selenium solution. I wish to coverherein the addition of from one-sixth to oneeighth of a gallon ofpolyselenide solution to one hundred gallons of water containing aboutonethird of a gallon of emulsified mineral oil.

A very effective spray giving practically one hundred per cent kill ofspiders and eggs is made by adding one-sixth of a gallon potassiumammonium seleno-sulphide solution (disclosed in my copendingapplication) to one-third of a gallon of emulsified oil in one hundredgallons of water. This spray is as effective as oil at one and one-halfper cent, or as lime sulphur at two per cent concentration, and has nobad effects on citrus or other trees, whereas either lime sulphur or oilat the concentration necessary to use to kill red spiders and their eggsfrequently causes severe damage to the trees.

This oil combination is an important feature.

It is well known that a minimum of one and onethird per cent of oil isnecessary to control red spiders, whereas I have found it necessary touse a maximum of only one-third of one per cent of oil. This iscommercially important, because oil at one and one-half per centconcentration cannot be used under all climatic conditions, nor can itbe used at certain seasons of the year, because of injury to citrustrees. My selenium oil spray can be applied under any condition ofweather or growth, without injury to the tree,

fruit, blossoms, buds, etc. The spray is very effective givingsubstantially one hundred per cent kill of spiders and eggs.

Moreover, the oil in combination with the substances of my abovementioned copending application is very eifective for the purposeherein.

Again it is noted that the high toxic effects of the complex seleniumpolysulphides of this invention when mixed with oil prepared as abovementioned seems to result in a modification of both seleniumpolysulphide and oil which amounts to something more than mere addition,and which is, in effect, a multiplication of toxic effect not obtainableby either one alone, unless each is used in relatively highconcentration.

Insofar as I am aware, no one has ever discovered that solutions of thepolysulphides with selenium have such a powerful toxic effect on redspiders and their eggs, without injury to the plant at any stage of itsgrowth.

I claim as my invention:

1. An insecticide containing a polyselenide of an alkali metal.

2. An insecticide containing a polyselenide of a metal selected from thegroup consisting of alkali metals and alkaline earth metals.

3. An insecticide containing a polyselenide of a metal selected from thegroup consisting of alkali metals and alkaline earth metals, in oil.

CHARLES B. GNADINGER.

